User interface and viewing workflow for mammography workstation

ABSTRACT

This invention provides a simple user interface and sequencing viewing method for a mammography interpretation workstation. In particular, the invention includes the method and apparatus that moves the source images and the associated data using two-level of pre-fetching and caching mechanism, sequences the reading workflow (including worklist, hanging protocol, viewing sequencing), draws markup using electronic grease pan, and automatically generates the recall forms and screening reports. The user interface operates on single button and mouse wheel style to maximize the radiologists&#39; efficiency.

CROSS-REFERENCE TO RELATED APPLICATIONS U.S. PATENT Documents

1. U.S. Pat. No. 6,630,937 October 2003 Kallergi et al. “Workstationinterface for use in digital mammography and associated method”

Other Publications

2. Robert A. Schmidt “Digital Mammography, networking, PACS, and Dante'sInferno” Applied Radiology, Supplement to September 2006, p21-25.

3. Gillian M. Newstead “Digital Mammography: Cost and Workflow Issues”Applied Radiology, Supplement to September 2006, p17-20.

4. Eric A. Berns et al. “Digital and Screen-Film Mammography: Comparisonof Image Acquisition and Interpretation Times” AJR Women's Imaging: 187July 2006, p38-41.

5. Laszlo Tabar et al “Teaching Atlas of Mammography”, Thieme Stuttgart,New York 2001

6. Laszlo Tabar et al “Breast Cancer: The Art and Science of EarlyDetection with Mammography—Perception, Interpretation, HistopathologicCorrelation” 2005 Georg Thieme Verlag

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISC APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of medical imagingsystems. Particularly, the present invention relates to a method andapparatus for a soft-copy reading mammography interpretationworkstation.

The U.S. patent Classification Definitions: 345/418 (class 345, ComputerGraphics Processing and Selective Visual Display Systems, subclass 418Computer Graphics Processing); 345/501 (class 345 Computer GraphicsProcessing and Selective Visual Display Systems, subclass 501 ComputerGraphic Processing System); 378/37 (class 378, X-Ray or Gamma Ray Systemor Devices, subclass 37 Mammography); 382/173 (class 382 Image Analysis,subclass 173 Image Segmentation).

Digital mammography images are very data-intensive. A standard 4-viewstudy acquired on a digital system with a 50 μm detector can containmore than 140 MB of data. When displaying such mammographic images ondual 5 MP (5 mega pixel) monitors, the radiologist is really seeing only7% of the information. One of the issues that radiologists face is thatmany of the tools that they use, such as an interpretation workstation,are relatively primitive when it comes to dealing with such largeamounts of data ([1]).

Screening mammography reading requires high throughput due to the largevolume of screen mammograms and the low reimbursement rate.Historically, screening mammograms on film tend to be read in batcheswith the average interpretation time per case being around 1 minute,including dictation. However the median film reading time may be asshort as 15 seconds because the vast majority of screening cases arenegative.

A number of studies ([2] and [3]) have showed that radiologists take asignificantly longer time for interpretation when reading digitalmammography cases as compared to the time for screen-film mammography.Reasons for this increase in reading time include the poor performanceof data transactions and inappropriate viewing workflows formammography. These needs are not well- addressed in current PACSworkstations.

BRIEF SUMMARY OF THE INVENTION

This invention provides a method and apparatus to overcome thelimitations from current PACS workstations by providing a system that

(1) customizes mammographic-specific reading and hanging protocolsequences for both screening and diagnostic study;

(2) streamlines reading workflow from opening a study to generating areport using a single button and mouse wheel;

(3) compares current exam with multiple prior exams and each prior examis accessible by single click;

(4) high-lights the current images in all hanging protocols to minimizethe risk of misdiagnosis from priors;

(5) incorporates expert film viewing methodology into digital, includingTabar's systematic viewing masks to enhance perception of subtleradiographic abnormalities;

(6) navigates by mouse wheel to view full-resolution image and visuallytraces pixels that have been viewed—no need to manually pan and zoom theimages to view all pixels at full resolution;

(7) allows user to use electronic grease pen to markup the image anytime; and automatically generates a corresponding mammography recallform and screening report;

(8) integrates the markup information with Reporting System.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 shows the navigation and image screens.

FIG. 2 shows the configuration of the reading sequence.

FIG. 3 shows viewing sequencing workflow.

FIG. 4 shows two-level caching.

FIG. 5 shows highlight current exam.

FIG. 6 shows single click to access multiple priors.

FIG. 7 shows systematic digital viewing technique.

FIG. 8 shows mouse wheel navigation of all pixel viewing.

FIG. 9 shows electronic grease pen and report generation.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides a simple user interface and sequencing viewingmethod for a mammography interpretation workstation. In particular, theinvention includes the method and apparatus that moves the source imagesand the associated data using two-level of pre-fetching and cachingmechanism, sequences the reading workflow (including worklist, hangingprotocol, viewing sequencing), draws markup using electronic grease pan,and automatically generates the recall forms and diagnosis reports. Theuser interface operates on single button and mouse wheel style tomaximize the radiologists' efficiency.

FIG. 1. Navigation Screen:

The workstation consists of two display screens: navigation screen andimage screen (although two screens may physically reside on a samemonitor; or one of two screens may physically reside on more than twomonitors). The navigation screen (see FIG. 1) is used for navigatingpatient/exam list; or for navigating hanging protocol; or for navigatingviewing protocol; or for displaying color ultrasound images; or fordisplaying color MRI uptake curve or map images; or for displayingdigital captured paper reports. The image screen is used to displayhigh-resolution gray-scale mammogram images and associated overlays forthe purpose of primary interpretation by radiologists.

FIG. 2. Configuration of Reading Sequence

The reading sequence includes:

Step 1—Overall viewing of 8 standard 4-view mammograms from current andprior exams. This step provides an overall viewing for radiologists tomake breast composition estimation (BIRADS breast density). Overallviewing of current and prior views also enhances the detection of tissuedensity changes; and overall viewing of the CC and MLO alternative viewsenforces the detection on both view projections.

Step 2—Assess image quality. The workstation provides bilateral orunilateral 2-view hanging protocols and a check list for qualityassurance. The check items can be entered by users, which typicallyinclude checking if missing any images; if properly positioned withadequate breast compression; if sufficient image quality for makediagnosis; and if images are labeled correctly.

Step 3—Same view or breast comparison between current exam and priorexam to enhance the detection of tissue density changes andcalcification appearance or disappearance on the same view.

Step 4—Systematic perception viewing, which is based on the expertviewing methodology that has been using for viewing films.

Step 5—Full-resolution all pixel image viewing for efficient searchingthrough all pixels in an image.

Step —Finding review and report generation.

Each step has a number of associated hanging protocols, such as, 2×4layout with current exam of 4 images display on left and prior exam of 4images on right for over viewing step; or 1×2 layout with 1 currentimage on left and prior on right for same view comparison step etc.

User uses a visual configuration tool to define his or her viewing stepin the viewing sequence, and the corresponding hanging protocols foreach step (see FIG. 2). For all hanging protocols defined in theconfiguration tool, the workstation automatically performs the chestwall and/or tissue or muscle alignment using a breast mask bounding box.

FIG. 3. One Button Sequencing Viewing Workflow:

Each hanging protocol with each viewing step is stepped by a single“moving forward” button (or “backward” button). This button is availableon both navigation screen and image screen (see FIG. 3). By clickingthis button, or equivalently using the (right) arrow key, it leadsthrough all configured viewing steps and all configured hangingprotocols.

Any operation that might be used within each hanging protocol andviewing step can be performed by clicking the up or down button, orequivalently using the arrow key or mouse wheel. For example, in thestep of systematic viewing, the mouse wheel moves the mask up or down.Or in the step of full-resolution all pixel viewing, the mouse wheelmoves the trace of viewing window up or down.

FIG. 4. Two-level On-Demand Pre-fetching/Caching:

The key design to ensure that image data is available on the screenalmost immediately is to optimize the performance seen by the user oncethe user opens next case. In order to achieve this impression, thesystem performs so-called two-level on-demand pre-fetching/cachingmechanisms:

The first level of the on-demand method ensures that the data resides onthe workstation prior to the initiation of the display. This mechanismis referred to as “pre-fetch” of images. While it can be imagined thatimages can be retrieved rapidly on demand from an archive, existingsystems, and certainly sites with high workloads on their networks, willnot see usable interactive speed without pre-fetching. Thus thearchitecture designed here will explicitly include pre-fetching,utilizing a “reading worklist” to order the cases for retrieval.

The second level of the on-demand method ensures that the data is in thecomputer memory once the user navigates to a case by providing anexplicit mechanism to make the next available case resident in systemmemory prior to the user navigating to that case. The mechanism to get acase into memory prior to its display is here referred to as “caching”.

This architecture is plotted in FIG. 4.

FIG. 5. High-lights Images from Current Exam:

The workstation is able to simultaneously display a set of current andprior screening mammogram images. In order to minimize the risk ofmisdiagnosis from prior exam, all the current images are high-lightedwith a frame. This applies to all hanging protocols (see FIG. 5). Someof diagnosis tools, such as, markups for recall, are designed to bedisabled to ensure that the diagnosis is made over the current exam.

FIG. 6. Single click to access multiple priors:

The stepping button can be used to step through each prior exam. Thesystem can also be configured so a separate looping button can be usedto step through each prior.

FIG. 7. Tabár's Systematic Viewing Masks

The systematic viewing approach developed for the workstation is basedon the expert viewing methodology that has been using for viewing films(see [4] and [5]). The essence of screening is to confidently reassurepatients that their normal mammograms are indeed normal, while at thesame time to find the occasional abnormality with great reliability. Thesystematic viewing method enables the radiologist to differentiate withconfidence between the normal and the abnormal tissue by accounting forthe radiopaque structure components that are seen against theradiolucent background.

The idea of the systematic viewing is to use two types of “mask” toenhance perception of subtle radiographic abnormalities. The horizontalmask is moved step-by-step, cranial-caudal either on the bilateral MLOviews or the bilateral CC views. The oblique or vertical mask is movedaway from the pectoral muscle or chestwall on the bilateral MLO views orCC views. By use of the masks, special attention can be given toasymmetric densities in regions with a high probability of malignantlesions (see FIG. 7).

FIG. 8. Mouse Wheel Navigating of Full-resolution Image

With the currently available monitors (5 MP), only a portion of an imagecan be displayed at one time at full resolution (in actual pixels).Manually panning and zooming on the computer monitor, while possible, isnot natural for radiologists, it can be inefficient, and it isphysically tiring and time-consuming. Automation of the viewing path foractual pixels will help to improve reading speed and reduce eye strainand finger tiredness.

The automation of the path to scan a full resolution image can becalculated from the image dimension and the display resolution in orderto cover the full image in an electronically magnified viewport (seeFIG. 8 a).

The electronic magnify glass can be manually roam through an image undercontrol of the user. The workstation then provides visual information ifall actual pixels in the images has been roamed through by theelectronic magnify glass (see FIG. 8 b).

FIG. 9. Electronic Grease Pan:

The workstation provides an “electronic grease pen” to allow the user tomarkup on the image display in any hanging protocol in any viewing step(see FIG. 8). The markups are considered as initial findings, and can beremoved by user. The display of the electronic markup can be toggled onand off. The electronic markup is automatically captured and itsposition information is automatically reflected in the report (see FIG.10).

1. In a system that provides user interfaces for radiologists toeffectively and efficiently perform mammography interpretation task, amethod for reading mammogram images, comprises: two-level of cachingmechanism in order to open a study immediately; image screens andnavigation screen; visual configuration user interface for end-user todefine the viewing sequence and hanging protocols; image display; userinterface for reading images; recall and screen report generation. 2.The method of claim 1, wherein said the viewing sequence comprises:overall viewing step to display current standard 4-view mammograms andprior standard 4-view mammograms on the image screen; assess imagequality step to display current study in 2-view hanging protocol; and tomarkup any quality issue if any; and to make correction if possible; andto communicate the quality issue with acquisition system according tocommunication standard; current and prior comparison step to displaysame view from current and prior exams on the image screen; systematicperception viewing step to overlay the mask graphics over a pair ofimages; full-resolution all pixel viewing step to sequentially displayall regions of the image in actual pixel; finding markup and review stepfor generating reports.
 3. The method of claim 2, each viewing stepwherein said the viewing sequence: can be configured to include andexclude in the view sequence; single button click user interface to stepthrough each viewing step (including the hanging protocol sequence). 4.The method of claim 2, the hanging protocols for each viewing stepcomprise: 2×4 layout for current and prior mammograms, or standard4-view mammograms plus extra view mammograms; 1×2 layout for a pair ofmammograms either bilateral, or unilateral, or same view of current andprior exams; 1×4 layout for standard 4-view mammograms any layout foruser defining any hanging protocol.
 5. The method of claim 2, whereinsaid the overview step and the current and prior comparison step, userconfigured stepping user interface comprises: stepping user interface tostep through each prior exam; stepping user interface to loop througheach prior exam.
 6. The method of claim 2, wherein said systematicperception masks, comprises: oblique mask align to the pectoral muscleoverlay on two bilateral MLO mammograms or same MLO view of current andprior mammograms; horizontal mask overlay on any bilateral mammograms orsame view of current and prior mammograms; vertical mask overlay on apair of CC mammograms.
 7. The method of claim 6, wherein said obliquemask and vertical mask, can be moved toward nipple or toward chestwallwith user defined step distance.
 8. The method of claim 6, wherein saidhorizontal mask can be moved toward top or toward bottom of image edgeswith user defined step distance.
 9. The method of claim 6, wherein saidsystematic perception masks, can be drawn in user defined graphic style,comprises: opacity of the mask; border color of the mask; borderthickness of the mask; mask angle and size.
 10. The method of claim 2,wherein said full-resolution all pixel viewing, comprises: automaticallycalculate the path to scan a full resolution image; user interface tosystematically move a region window along the calculated path to viewthe image in full-resolution; visual feedback using transparent graphicto track the regions that have been viewed.
 11. The method of claim 2,wherein said generating reports, comprises: user interface to markuplesion finding using electronic grease pen; screen capture of the markupand images; location of the lesion markup; type of the lesion markup;markup assessment; recall procedures.
 12. The method of claim 1, whereinsaid image display, comprises: chest wall and/or tissue or musclealignment using a breast mask bounding box; present images usingconfigured hanging protocol; high-light images from current exam;display clinical text information on opposite of chestwall.